Bisorganophosphorus esters and their preparation



United States Patent 3,097,997 BISORGANOPHOSPHORUS 'ESTERS AND THEIR PREPARATION Karoly Szaho, Yonkers, N.Y., and John G. Brady, Campbell, Calif-Z, assignors to Stautfer Chemical Company,

New York, N.Y., a corporation of Delaware No Drawing. Filed Nov. 7, 1961, Ser. N0. 150,624 8 Claims. (Cl. 167-22) This invention relates to bisorganophosphorus esters and, in particular, to bisesters of phosphonothioic acid in which two phosphonothioic acid residues are connected through their sulfur atoms by a thioalkylene bridge. The invention is also concerned with biocidal compositions, including their preparation and which have, as the active component thereof, at least one of the aforementioned bisesters of phosphonothioic acid.

The bisphosphonothioic esters as contemplated herein can be generally depicted by the following formula:

wherein R and R refer to lower alkyl radicals preferably those having from 1 to 4 carbon atoms and n is an integer of from 2 to 3. The alkyl groups include both normal and branch chains and may be alike or different. Illus trative compounds falling within the ambit of the above depicted formula include the following specific structures:

Qompound 8 The bisorganophosphorus esters of this invention are susceptible to a generalized method of preparation which comprises condensing, preferably in the presence of a 3,097,997 Patented July 16, 1963 basic condensing agent, about one mole of a dihalodialkylsulfide of the following formula:

wherein n has the significance previously designated and X represents a halogen atom, i.e. chlorine, bromine and the like with about 2 moles of a lower alkyl ester of phosphonothioic acid. The reaction is schematically in dicated by the following equation:

wherein X, R, R and n have the meaning previously defined. It has been our finding that generally excellent results and yieids are obtained by heating the phosphono thioic acid and dihalodialkylsulfide in approximately 2 to 1 molar ratios in a relativeiy inert normally liquid organic solvent in the presence of a tertiary amine as the basic condensing agent. Suitable solvent mediums are exemplified by liquid aromatic hydrocarbons such as benzene, toluene, xylene etc, saturated aliphatic hydrocarbons such as hexane, heptane, cyclohcxane etc. and saturated aliphatic ethers. Basic condensing agents which have been found satisfactory for effecting the reaction include basic organic amines, preferably tertiary amines as represented by the lower trialkylamines, e.g. trimethylamine, triethylamine etc, tertiary heterocyclic amines such as pyridine, picoline, quinoline, etc., inorganic bases and basic salts, e.g. alkali metal carbonates, e.g. sodium carbonate, potassium carbonate and the like. In some instances the reaction is advantageously performed in a medium capable of functioning both as a solvent and as the basic condensing agent. Pyridine and quinoline are examples of such dual purpose solvents.

Reference is now made to the following examples which are presented for the purpose of illustration only since variations in practicing the invention without departing from the spirit or scope thereof will be apparent to those skilled in the art to which the said invention pertains.

EXAMPLE 1 9 impr son?s-oms-i cnn i U 02H; 0 C2115 11.4 g. (0.2 M) of potassium hydroxide was dissolved in 25 ml. of water and the resulting solution combined with a mixture of 50 ml. of alcohol and 12.5 ml. of water. To this was added with stirring 0.1 M of O-ethyl ethylphosphonochloridothioatc. A spontaneous reaction occurred which gradually subsided as the addition was completed. The reaction mixture was maintained at -70 C. for one hour, after which period 6.6 g. (0.05 M) of bischloromethylsulfide was introduced and the resulting mixture refluxed for 10 minutes. After the contents of the flask. had cooled to room temperature, 250 ml. of

- water was next introduced and the aqueous solution extracted three times with fresh portions of benzene. The organic extracts were combined, dried over anhydrous calcium sulfate, treated with charcoal and filtered. The benzene was removed under reduced pressure leaving a residual oily product corresponding in structure to the above depicted formula and having a refractive index of 1.4928 at 25 C.

3 EXAMPLE 2 polyoxyethylene surface active agents. The proportion of these agents commonly comprises 1-15 by weight of the pesticidal compositions although the proportion is not critical and may be varied to suit any particular situaour, 0 alls 5 tion.

This preparation was patterned after the procedure of other j cts may be resorted to in compou h fi example except h t bi djchlorocthylgulfide, biocidal formulations based on the herein described ort d was d i t d f th bi hl th l. ganophosphorus esters and, in this connection, reference ulfide ()f the previous xample. Theq'e was obtained an is made 110 adhesives, Spreaders, activators, fertilizers and almost colorless oil having a refractive index of 1.5'160 thfi like- The Preparation of Pesticidal COH'IPOSMOIIS i at 25 C. The chemical constitution of the product corcorp P P eSKiYS f t i invention responded to the structural formula as above depicted. and the results of testing Such Compositions are Spelled out in the following test procedures: EXAMPLE 3 Acaricidal evaluation test-The two-spotted mite, terranychus telarius (Linn), is employed in tests for acaricides. Young pinto bean plants are infested with several ClCH2l-SCH2-SCHz-S-l-CIIzCl hundred mites. Dispersions of test compounds are preocgm (M32115 pared by dissolving 0.1 gram of the toxic material in ten milliliters acetone. This solution is then diluted with Using approximately 2 moles of O-ethyl chloromethylwater containing 0.015% Vatsol (sodium salt of isopropylphosphonochloridothio ate and one mole of bischloronaphthalene sulfonate) and 0.005% Methocel (methmethylsulfide, the procedure of the previous examples was ylated cellulose) as emulsifiers, the amount of water hecarried out. There resulted an oily product, having a ing sufficient to give concentrations of active ingredient chemical structure corresponding to the above given forranging from 0.25% to 0.005% The test suspensions are mula. The results and yields of this example, generally, then sprayed on the infested pinto bean plants. After coincided with those obtained with the previous examples. seven and fourteen days, the plants are examined both for As stated elsewhere herein, the organophosphorus esters post-embryonic forms of the mite as well as eggs. The of this invention are eminently useful and suitable for percentage of kill is determined by comparison with concornbating a variety of pests of the type which fall in the trol plants which have not been sprayed and the LD-50 lower orders of classification and which are exemplified 39 value calculated using well-known procedures. LD50 by cockroaches, milkweed bugs, confused flour beetles, values are reported under the columns 2 SM and 2 SM house flies, two-spotted mites and the like. It is to be eggs" on the table below. understood that the ltoxicants of the invention may be Insecticidal evaluation tests.Four insect species are used directly on the adult pest organism or, in some insubjected to evaluation tests for insecticides: stances, applied to the eggs. In either case, the end result is to eradicate or control the pest organism. Amerlcan cockroach P William?! flmericalla As those in the art are well aware, various techniques are available for incorporating the active component or Milkweed bug OHCOPEUHS fflsciallls toxicant in suitable pesticidal compositions. Thus pes- Confused flour beeflfi Tfl'boll'llm confusllm ticidal compositions can be conveniently prepared in the 40 form of liquids or solids, the latter preferably as ho- House y Mu-Ym domfslica mogenfious here-flowing dusts commonly fofmulated Y The procedure for insects is similar to the miticidal admixing the active component with finely divided solids testing prwedum Test insects are Caged in cardboard or carriers as exemplified by talc, natural clays, diatomailing tubes 1 in diameter and 5 {an The cages 1113030115 earth, Various flours such 35 Walnut 511611 Wheat, are supplied with cellophane bottoms and screened tops. S" beal'hwlton Seed and so forth- Ten to twenty-five insects are used per age. Food and Liquid compositions are also useful and normally co-mmare Supplied in each cage The f d flour Prise a dispfirsion the tQXiCaTlt in a liquid media For beetles are confined in petri dishes without food. The instance, it may be convenient to dissolve the toxicant 50 Caged insects are sprayfid with the active compound at directly in a solvent suchas kerosene, fuel oil, xylene, various concentrations, After 1wemy-f0ur and seventyalkylated naphthalenes of the like and I156 Such Organic two hours, counts are made to determine living and dead solutions directly. However, it is more common proceinsctS time to p y dispersions of the toxical'lt in an aqueous House fly evaluation tests differ in this respect: the media and Such Compositions y ht? Produced y forming toxioant is dissolved in a volatile solvent, preferably acea concentrated solution of the toxicant in a suitable ortone, the active compound is pipetted into a petri dish s solvent followed y dispersion in Water, us ally bolt-om, allowed to air dry and placed in acarclboard mailwith the aid of surface active agents. The latter, which ing t be, Twenty-five f l fli are caged i th t b may be the anionic, cationic or nonionic types, are exem- The flies are continuously exposed to the known residue plified by sodium stearate, potassium oleate and other of the active compound in the cage. After twenty-four alkaline metal soaps and detergents such as sodium lauryl and forty-eight hours, counts are made to determine livsulfate, sodium naphthalene, sulfonate, sodium alkyl ing and dead insects. The LD50 values are calculated naphthalene sulfonate, methyl cellulose, polyoxyethylene, using well known procedures, and reported on the table fatty alcohol ethers, polyglycol fatty acid esters and other below.

House American Milkweed Confused 2-Spottcd 2-Spotted Salt Marsh 2-Spotted Compound fly, g. Roach, Bug, flour mite, mite eggs, Catermite percent percent beetle, percent percent pillar, Systemic,

g. pereent p.p.1n.

3 t sit} M at} sari 7 l0 .1 .1 0 .005 0 1 We claim: 1. A bisorganophosphorous ester of the following general formula:

wherein R and R represent lower alkyl radicals and n is an integer of from 2 to 3.

2. A bisorganophosphorus ester of the following formula:

3. A bisorganophosphorus ester of the following formula:

4. A bisorganophosphorus ester of the following formula:

5. A method of killing pests which comprises applying to a pest habitat a small but effective amount of a hisorganophosphorus ester having the following general formula:

0 0 H5CP-i '-SOHgsCH3S-i -C:H5

O CiHs O 01H 7. A method of killing pests which comprises applying to a pest habitat a small but effective amount of a bisorganophosphorus ester of the following formula:

8. A method of killing pests which comprises applying to a pest habitat a small but effective amount of a bisorganophosphorus ester of the following formula:

References Cited in the file of this patent UNITED STATES PATENTS 2,653,161 Ballard et al Sept. 22, I953 FOREIGN PATENTS 515,666 Canada Aug. 16, 1955 1,190,783 France Oct. 15, 1959 

5. A METHOD OF KILLING PESTS WHICH COMPRISES APPLYING TO A PEST HABITAT A SMALL BUT EFFECTIVE AMOUNT OF A BISOTGANIPHOSPHORUS ESTER HAVING THE FOLLOWING GENERAL FORMULA 